1. Field of the Invention
This invention relates to a disk drive suspension used in a disk drive for an information processing apparatus, such as a personal computer.
2. Description of the Related Art
A hard disk drive (HDD) is used in an information processing apparatus, such as a personal computer. The HDD comprises a magnetic disk rotatable about a spindle, a carriage turnable about a pivot, etc. The carriage, which comprises an actuator arm, is turned transversely relative to tracks about the pivot by a positioning motor, such as a voice coil motor.
A suspension is mounted on the actuator arm. The suspension comprises a load beam and flexure superposed thereon. A slider, which constitutes a magnetic head, is mounted on a gimbal portion formed near the distal end of the flexure. The slider is provided with elements (transducers) for accessing data, that is, for reading and writing. If the disk rotates, the slider slightly flies above its surface, and an air bearing is formed between the disk and slider.
The gimbal portion comprises a tongue portion on a part of the flexure. The slider is mounted on one surface of the tongue portion. A protuberance called a “dimple” is formed at the distal end portion of the load beam. The dimple protrudes from one surface of the load beam toward the tongue portion. The reverse side of the dimple is depressed in the other surface of the load beam.
As the tip of the dimple contacts the tongue portion, the tongue portion is supported so as to be swingable around the dimple tip. The slider, along with the tongue portion, makes a swinging motion (gimbal motion) around the dimple. In order to enable the slider to swing horizontally equally, the dimple needs to be formed on the transverse center of the slider.
The disk drive is expected to have a higher recording density and be small. Therefore, the slider should be positioned more accurately than previously. Means for accurately positioning a slider is proposed in Jpn. Pat. Appln. KOKAI Publication No. 2005-135467 (Patent Document 1).
On the other hand, sliders with various functions have also been proposed. For example, a slider is provided with circuit components for heat control and the like. One such slider is described in Jpn. Pat. Appln. KOKAI Publication No. 2009-123282 (Patent Document 2). Built-in functional components of the slider tend to be diversified. Thus, the number of terminals on the slider is apt to increase, and the pitch between the terminals is liable to be reduced. If the positional accuracy of the slider is poor, in this case, electrical connection between the slider terminals and terminals at the tongue portion may fail. Therefore, the positional accuracy of the slider needs to be increased. Further, the positional relationship between the slider and dimple should be regulated more accurately.
The flexure is secured to the load beam by laser welding or the like. Therefore, the mounting position of the flexure on the load beam can be regulated only with limited accuracy. In Patent Document 1 mentioned above, a dimple is disposed on a load beam. Despite maximally accurate regulation of the dimple position on the load beam, in this case, the positional accuracy between the dimple and slider inevitably worsens if the accuracy of the mounting position of the flexure on the load beam is poor.
Thereupon, a proposal has been made to increase the positional accuracy between a slider and dimple by forming the dimple on a tongue portion. In this case, the slider is secured to one surface (slider mounting surface) of the tongue portion by adhesive, and the dimple to the other surface.
The dimple requires some height to secure an allowed range of gimbal motion of the tongue portion. If the dimple is low-profiled, a part of the tongue portion interferes with the load beam when the swing angle of the tongue portion increases, so that the allowed range of gimbal motion is inevitably reduced. Thus, the dimple size cannot be reduced unlimitedly.
If the dimple is formed on the tongue portion, its reverse side defines a recess in the slider mounting surface of the tongue portion. If a small slider is mounted on the slider mounting surface of the tongue portion with a dimple of the conventional size, the ratio in size of the recess on the reverse side of the dimple to the slider increases. In the case of a miniature slider, in particular, the recess may cause the slider to tilt or reduce the bond strength of the slider on the tongue portion.